Hewlett-packard Development Company, L.p.

David Sikharulidze

Laura Kramer

Gregg Combs

Jeff Mabeck

A nematic bistable liquid crystal (LC) display element includes a substrate having an inner surface alignment layer and a pair of in-plane electrodes in proximity to the substrates. The display element has charged electrophoretic nanoparticles in the LC medium configured to setup a matrix with the LC when an electric field is applied to the electrodes.

Bistable liquid crystal element

A display device for displaying an image includes a display cell with a first cell wall and a second cell wall opposed to the first cell wall. The cell walls enclose a layer of a display medium that includes a liquid crystal material having finely-divided pigment particles dispersed therein. Each cell wall includes an electrode for applying an electric field across the display medium. A method for recording an image is also provided.

Display

A multi-stable electrophoretic display device has a plurality of pixels and comprises a first substrate and a second substrate. The substrates are spaced apart from each other and enclose a layer of an electrophoretic medium comprising a liquid crystal material having finely divided pigment particles dispersed therein. The device further comprises electrodes for formation of a pixel area outline and applying an electric field across at least some of the electrophoretic medium in the pixel area. The electrodes occupy substantially less than the entire field of view of the display pixels and can be used to effect switching between a first optical state in which most incident light on a pixel does not impinge on a pigment particle, and a second optical state in which most incident light on a pixel impinges on pigment particles.

Electrophoretic display device

An aspect of the invention provides a method of recording an image, comprising: providing a display cell having a first cell wall and a second cell wall opposed to the first cell wall, the cell walls enclosing a layer of a display medium comprising a liquid crystal material having finely-divided pigment particles dispersed therein, each cell wall including an electrode for applying an electric field across the display medium; applying via the electrodes a first electric field of a first polarity and of sufficient magnitude and duration to cause the particles to migrate and accumulate at the first cell wall; illuminating at least some of the particles with an image to be recorded; and applying via the electrodes a second electric field of opposite polarity to the first polarity and of sufficient magnitude and duration to cause some but not all particles to migrate from the first cell wall so as to produce a recorded image.

A bistable liquid crystal display device has a nematic liquid crystal which is switchable between two different stable molecular configurations. The liquid crystal has a mixture of finely-divided positively-charged particles and finely-divided negatively-charged particles dispersed therein.

Bistable nematic liquid crystal display device

A bistable nematic liquid crystal display device includes two cell walls enclosing a layer of a nematic liquid crystal material, means for applying an electric field across at least some of the layer, and means for inducing local planar alignments of said liquid crystal material at an inner surface of each cell wall. The local planar alignments are oriented to each other at an angle greater than 0&#xb0; and less than 90&#xb0;. The device also includes means for selectively masking an alignment effect of either of the local planar alignments by applying a unidirectional electric field pulse of suitable magnitude and duration to stabilise the device in one of two different homeoplanar configurations determined by the polarity of the pulse.

Bistable liquid crystal display device

A reflective colour display device comprising a display element including two opposed cell walls enclosing a layer of an electro-optic material, each cell wall being provided with at least one electrode on an inner surface thereof for applying an electric field across at least some of the electro-optic material, and a selective reflector on one of said cell walls, wherein the electro-optic material is electrically-switchable between a first state in which the display element will diffusely reflect substantially all wavelengths of visible light transmitted by the selective reflector, and a second state in which the display element will reflect light transmitted by the selective reflector at a substantially lower intensity than it does when the electro-optic material is in the first state.

Reflective color display device with selective reflector directly coupled to outside surface of cell wall of display element

A method of manufacturing a bistable liquid crystal device comprises initially forming a cell from first and second opposed spaced-apart cell walls () enclosing a layer of nematic liquid crystal material () having a photopolymerizable polymer precursor dissolved therein. Electrodes () for applying an electric field across at least some of the liquid crystal material are provided on at least one cell wall. The inner surface of at least the first cell wall is provided with a grating alignment structure (), and the cell is illuminated with suitable light to effect photopolymerization of the polymer precursor through the first cell wall. This causes polymerization to occur close to the first cell wall and deposition of the resulting polymeric material as a coating on the grating alignment structure on the first cell wall.

Bistable nematic liquid crystal device

A bistable nematic liquid crystal display device comprises two opposed cell walls enclosing a layer of a nematic liquid crystal material. An inner surface of each cell wall is provided with an electrode for applying an electric field across at least some of the liquid crystal material. An inner surface of one of the cell walls is provided with a surface alignment capable of inducing a desired alignment in adjacent molecules of the liquid crystal material, and a layer of finely-divided particles is immobilized on the surface alignment.

An electrophoretic liquid crystal display device comprises:

Electrophoretic liquid crystal display device

A bistable nematic liquid crystal display device comprises two cell walls enclosing a layer of nematic liquid crystal material having finely divided solid particles dispersed therein. At least one electrode on each cell wall applies an electric field across at least some of the liquid crystal material. Surface alignments on the inner surface of both cell walls induce adjacent molecules of the liquid crystal material to adopt desired orientations. The liquid crystal material adopts two different stable molecular configurations according to the polarity of applied electric field pulses.

A bistable liquid crystal device is made from a cell having first and second opposed spaced-apart cell walls enclosing a layer of nematic liquid crystal material having a photopolymerisable polymer precursor dissolved therein. Electrodes for applying an electric field across at least some of the liquid crystal material are on at least one cell wall. The inner surface of at least the first cell wall has a grating alignment structure. The cell is illuminated to photopolymerize the polymer precursor through the first cell wall. This causes polymerization close to the first cell wall and deposition of the resulting polymeric material as a coating on the grating alignment structure on the first cell wall.

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Bristol, United Kingdom

David Sikharulidze